Is Data Helping Or Hurting Your Workout?

There was a day when wearable tech was limited to Silicon Valley execs and your office IT guy. Now, Fitbit, Nike+ Fuel Band and Jawbone UP bracelets have become regular tools for the athletically-inclined, and fitness gadgetry has grown into a $70 billion annual business in the U.S., according to the Consumer Electronics Association. But there’s a right and a wrong way to plug in your workout, says Anthony Wall, director of professional education at the American Council on Exercise.

“You see people running down the street with three body monitoring devices on and an iPhone GPS tracking their route,” says Wall. “It’s a lot of great data, but what will you do with it?"
The Upside: You Can Monitor and Motivate. These devices are only one tool in improving your workout, says Wall, and you’ll get lost if you think technology will bring you results. The job of tech is to monitor—cadence, power, heart rate, steps taken, calories burned, distance, pace. It can provide clarity and direction for the way you’d like your training to progress, even motivation and accountability when shared with your fellow exercisers. But in the same way a compass won’t help you hike, buying a FitBit monitor won’t make you suddenly able to run three miles every day.

The Downside: You May Become Obsessed. And it’s easy to get caught up in the numbers, a tendency for performance-minded exercisers. How many calories have I burned? How many miles have I run? What is my power output on the bike? Number crunchers forget that not all devices are created equal—or accurate—and that those numbers should provide feedback, not become the goal. First, stop counting calories to count calories, says Kai Karlstrom, Tier 4 manager at Equinox at The Loop in Chicago. “It’s useful at the beginning of a program when someone is figuring out what’s right for his or her body, but beyond checking in every so often, it shouldn’t be necessary,” he says. Ditto for your weight and BMI. These numbers are markers, not data to be followed obsessively.

The Takeaway: Stay Tuned Into Your Body. As for interpreting in-workout stats, you need to learn how to correlate that info into how you’re feeling. The numbers alone aren’t the whole story. If cycling at 200 watts on the bike felt like a Zone 2 effort last week, but feels like a Zone 3 effort this week, it may be a sign that you need to ease off the intensity. The same goes for a heart rate that doesn’t drop in the first minute after finishing an interval or a faster-than-normal heart rate during a 3-mile run all because you didn’t sleep well the night before or you were stressed at work this week or you were fatigued.

Certain trainers have also begun looking at heart rate variability (HRV), a number that measures the body’s stress by the space between heartbeats. It can tell trainers the days you shouldn’t go hard because your central nervous system is overstressed, or the days when you can and your body will be able to properly recover.

It’s in these cases—when workouts increase in volume and intensity—that it’s most important to monitor data, says Karlstrom. “Like a trainer or coach, you can use that info to gauge the effectiveness of a program and make changes,” he says. “Remember, the data is only as good as the person interpreting it.”